The present invention relates to a tape counter for a rotary head type video signal recording and reproducing apparatus which counts and displays an amount of a tape by which the tape has run and a tape counting method therefor.
In a rotary head type video signal recording/reproducing apparatus (hereinafter simply referred to as VTR), to measure an amount of tape by which the tape has run during its use, a number of control signals is counted which have been recorded on the tape for each frame period along the lengthwise direction of the tape. The count value is converted on a time base and is displayed in a series of units of hours, minutes, and seconds.
Recently, 8-mm VTRs which use tapes having an 8 mm width have been put into practice. Each of four pilot signals(f.sub.1 to f.sub.4) having mutually different frequencies has sequentially been recorded on each tape track in the 8-mm VTR. In addition, 8-mm VTRs have adopted an ATF (Automatic Tracking Finding) method by means of which the pilot signals are used to perform an accurate tracking operation.
Since the above-described control signals are not recorded on the tape tracks if the ATF method is adopted in such 8-mm VTRs, the tape counter utilizing the presence of control signals described above cannot be used any more in the 8-mm VTR. Hence, a light reflecting board is installed on a reel bed of the 8-mm VTR and, the number of rotations of the reel bed is optically detected through the use of the light reflecting board. The amount of tape by which the tape has run is displayed, e.g., in a four-digit numerical representation.
In such 8-mm VTRs, the number of rotations of the reel bed is detected and the amount of tape by which the tape has run is displayed on the basis of the number of rotations of the reel bed. However, since the amount of tape by which the tape had run per revolution of the reel bed is different depending on a wrap diameter of the tape on the reel bed, an accurate display of the amount by which the tape has run cannot be achieved.